This invention relates to a motor vehicle headlight arranged to provide an additional lighting function.
French patent specification FR 2 694 373 discloses a motor vehicle headlight which gives two different lighting functions, such as the fog penetrating function and the main beam headlight function. However, this type of light is fixed, and therefore only illuminates straight ahead, that is to say in the axis of the vehicle. This is effective so long as the vehicle is travelling in a straight line so that the headlights give effective lighting of the potential positions of the vehicle if it continues to travel in that straight path.
However, when the vehicle is following curved paths, for example when travelling round bends in the road, the fixed headlight is no longer able to illuminate perfectly, or even moderately well, the path ahead. One possible solution to this would be to provide a specific headlight which would increase the number of headlights to be fitted within the available space at the front of the vehicle. This space is however limited.
An object of the invention is to provide a headlight which is capable of emitting a beam of light to illuminate the path ahead when the vehicle is following a non-straight path, without it being necessary to increase the surface area of the headlights.
According to a first aspect of the invention, a headlight for a vehicle, comprises a support, a lamp having first and second light sources, a first reflective surface and a second reflective surface, the said reflective surfaces being adapted to cooperate with the first and second light sources to emit first and second beams. At least the first reflective surface of the headlight is adapted to be displaced in rotation about an axis with respect to the support, whereby, when the vehicle is following a curved path defining a bend, the said first beam is adapted to be oriented towards the inside of the bend.
Thus, the path ahead is always illuminated by the headlight. The use of a lamp with two light sources enables two different lighting functions to be obtained in the same headlight, so that the overall optical surface area of the vehicle is not increased.
Preferably, the first reflective surface is in an upper part of the headlight.
Preferably, the second reflective surface is fixed with respect to the said first surface.
Preferably, the light is rotatable about the said axis.
Preferably, the said axis is arranged to extend vertically during operation of the headlight.
Preferably, the said first surface comprises a plurality of separate surface zones.
Preferably, the said surface zones are juxtaposed laterally to each other and are delimited by transition lines interrupting the slope in the curvature of the surface.
Preferably, the second surface is defined by a portion of a paraboloid having a focus situated close to the lamp and an axis substantially parallel to a main axis of the headlight.
Preferably, the first beam has a cut-off line.
Preferably, the said second beam corresponds to a main beam function of the headlight.
Preferably, it includes a shade or mask associated with the first surface for emitting the first beam in cooperation with the first light source of the lamp.
Preferably, the control unit is so arranged that the said rotation is a function of the amplitude through which a steering wheel of the vehicle is turned by a driver.
Preferably, the control unit is so arranged that the said rotation of the first surface is a function of vehicle speed.
Preferably, the control unit is so arranged that the illuminated or extinguished state of the first beam is a function of the amplitude through which a driver of the vehicle turns the steering wheel.
Preferably, the control unit is so arranged that the second beam is adapted to remain lit during the said rotation.
According to a third aspect of the invention, a vehicle has at least one headlight according to the above first aspect of the invention, or an assembly according to the said second aspect.
Further features and advantages of the invention will appear more clearly on a reading of the following detailed description of a preferred embodiment of the invention, which is given by way of non-limiting example only and with reference to the accompanying drawings.